THE INFLUENCE OF DIBORANE DOPING IN MICROCRYSTALLINE SILICON (MUC-SI:H) FILMS

Rosari Saleh

Jurusan Fisika Fakultas MIPA, Universitas Indonesia, Depok 16424

Abstract
The influence of diborane doping on the electrical and structural properties of microcrystalline silicon (muc-Si:H) films deposited using highly hydrogen diluted silane as the reactive gas in a plasma-enhanced chemical vapor deposition system have been studied. The diborane to silane (B2H6/SiH4) flow rate ratio has been varied from 2.0 x 10-2 to 1.0. The structural properties of the films were investigated by Raman spectroscopy. Electrical characterization has been carried out by temperature dependence dark conductivity and room temperature Hall effect measurements. The decrease in crystallite size and crystalline volume fraction with the addition of B2H6 to the source gas indicates that it decreases the crystalline phase in the films. The dark conductivity rises from 5 x 10-7 to 2.0 x 100 S/cm and then decreases to 5.0 x 10-3 S/cm, furthermore the carrier concentrations increase monotonically with increasing diborane to silane (B2H6/SiH4) flow rate ratio. The result show that the high conductive film consists of mixed phase of crystalline silicon embedded in amorphous network. The transport mechanism is discussed and related to the structural properties of the films.